Exemplary embodiments of this invention generally relate to environmental control systems of an aircraft and, more particularly, to operation of an environment control system while an aircraft is on the ground or in particular flight configurations.
Commercial jet aircrafts typically include environmental control systems (ECS) that regulate air supply, temperature, and cabin pressurization on the aircraft. Such an ECS may also be utilized to provide cooling to components of the aircraft itself, such as electrical systems. The ECS of most jet aircrafts typically includes two or more ECS packs which provide pressurized air of an appropriate temperature to the cabin of the aircraft. The ECS can utilize heated, pressurized bleed air or electrically driven cabin air compressors powered by the engine or auxiliary power unit of the aircraft. Ambient ram air that enters the aircraft through a ram scoop is typically used as the system heat sink.
When an aircraft is on the ground and its main engines are not being used, an alternative power source, such as an auxiliary power unit for example, may be used to supply power to support ground operations. During some ground operations, the ECS may continue to supply temperature controlled air to the cabin and onboard aircraft equipment. The alternative power source used to provide power when the aircraft is on the ground is limited and may not provide enough power to the aircraft to operate the entire ECS. For example, in an aircraft having an ECS that includes multiple air conditioning or ECS packs, the power provided may support only one of the ECS packs, rather than all of them.